Telephone call in space - somewhat elaborate (9)
I believe the answer is:
embellish
'elaborate' is the definition.
(thesaurus)
'telephone call in space somewhat' is the wordplay.
'telephone call' becomes 'bell' (bell can mean a phone call).
'in' is an insertion indicator.
'space' becomes 'em' (in typography, a space as wide as a letter 'm').
'somewhat' becomes 'ish' (eg 'amateurish' means somewhat amateur).
'em'+'ish'='emish'
'bell' going within 'emish' is 'EMBELLISH'.
(Other definitions for embellish that I've seen before include "Ornament, decorate" , "Improve story by adding invented details" , "Add false details" , "Improve story by adding invented touches" , "Add ornamental details, make more colourful" .)